This invention relates to a mangle for pressing damp laundry articles with rotatably mounted padded drums in the form of perforated hollow cylinders connected to a vacuum device. The drum surfaces contact and cooperate with trough shaped hollow bodies heated with high pressure steam, and the used hot air developed inside the drums and/or the condensate accumulating in the trough bodies is used to pre-dry the laundary articles.
With a known mangle the used air from the drums is used to heat a post dryer arranged behind the drums (German AS No. 1,666,740). The post dryer consists essentially of a box shaped heat chamber which works together with the laundry article transport or conveyor bands and which is heated by the used hot air. The transport bands guide the laundry articles into and press them against the heat chamber. The post dryer is arranged at the rear end of the mangle and can be folded up above the drums.
It is also known (German PS NO. 468,074) to channel the used air from the drums through a heat exchanger to heat fresh air, and then to use the warm fresh air to pre- and post-dry the laundry articles. The heated fresh air is supplied to boxes having perforated upper surfaces arranged before and after the mangle drums, and flows through the perforations to the laundry articles which are drawn thereacross.
The hot air and vapor from the drums is reused in these known mangles in order to recycle the exhaust air which would otherwise be released into the atmosphere, but such recycling is problematical in several respects. The post dryer of German AS No. 1,166,740 does not significantly increase the output of the mangle because it is not the conditions at the end but rather at the beginning of the mangle which are decisive. The post dryer also has a negative effect on the smoothing achieved by the mangle itself. When fresh air is blown freely through the laundry articles before and after the mangle, this fresh air being heated by the exhaust air from the mangle drums in a heat exchanger (German PS No. 468,074), this also adversely affects the operation of the mangle. The people working at the mangle are constantly subjected to a hot and steamy environment, and in addition the exhausted hot air from the drums is not effectively utilized.
With another known mangle (German PS No. 182,689) a drum and several trough shaped hollow bodies are spaced slightly apart, the condensate which accumulates in the hollow bodies is fed back through the tubes which serve to heat the air, and the air which is heated in this manner is applied to the laundry articles which move around the drum in the space between the drum and the hollow bodies.
With still another known mangle (German AS No. 2,814,618) having two drums situated one above the other and each having two trough shaped hollow bodies associated with it, the condensate which accumulates in the hollow bodies is taken to a heat exchanger for further heating and added to hot air already heated in a separate heat exchanger. This double heated air is then applied to the laundry articles as in German PS 182,689.
Using the hot condensate to heat air and using this heated air to dry the laundry articles in a press or mangle is disadvantageous in several respects. The utilization of the condensate heat is not optimal, for example, in the mangle of German PS No. 182,689 because a large proportion of the hot air is vented to the atmosphere as a result of the constantly running exhaust associated with the drums.
It is also known to pass the laundry articles for purposes of pre- and post-drying over the outside of the heated trough shaped hollow bodies (Great Britain No. 805,339 and German PS No. 600,141) and to press the laundry articles against the outside of the hollow bodies.
Cylinder mangles are also known in which the outer surface of a steam heated cylinder or drum is provided with pressure rollers, bands or plates which move at the same speed and in the same direction as the drum, and which guide the laundry articles and press them against the drum.